1. Field of the Invention
An embodiment of the present invention relates to a method, medium, and apparatus coding/decoding audio data, and more particularly, to a method, medium, and apparatus hierarchically coding/decoding audio data such as through bit sliced arithmetic coding (BSAC).
2. Description of the Related Art
There are two ways to transmit a bit sliced arithmetic coding (BSAC) payload to support a fine granular scalability (FGS) capability. The first way is to drop elementary streams for a BSAC access unit. In this case, the access unit is defined as an independently accessible portion of an elementary stream. The access unit is the smallest data unit that can contain timing information. The second way is to truncate the BSAC payload on a server side providing audio data, that is, a coder side. The former occurs on a sync layer and a deliver layer, while the latter occurs on a compression layer. The two techniques can also be used simultaneously.
When a bit-stream is transmitted to a decoder by hierarchically coding audio data in a coder using the aforementioned transmission techniques, a problem conventionally lies in that there is no solution to effectively transmit the hierarchically coded audio data along with extension data that can form audio data, such as data for extending a channel of audio data to a multi-channel, data for extending a bandwidth of audio data, and data for generating a cyclic redundancy code (CRC) for checking a transmission error of audio data, for example.
Accordingly, there is a need to overcome these conventional drawbacks.